The roles of NOD like receptors in inflammation are different between Japanese and Caucasian

Nucleotide oligomerization domain polymorphism confers no risk to Guillain-Barré syndrome

OBJECTIVES

Nucleotide oligomerization domain (NOD) proteins are cytoplasmic receptors that play important roles in host innate immune responses to pathogens by recognizing self or non-self-molecules and have been implicated in many autoimmune diseases including Guillain-Barré syndrome (GBS). The current study investigated whether NOD polymorphisms (NOD1-Glu266Lys, rs2075820, and NOD2- [Arg702Trp, rs2066844 and Gly908Arg, rs2066845]) contribute to ligand sensing and thus affect the susceptibility and/or severity of GBS.

MATERIALS AND METHODS

We determined single nucleotide polymorphisms (SNPs) of NOD gene (NOD1-Glu266Lys and NOD2-[Arg702Trp; Gly908Ar]) in 303 patients with GBS and 303 healthy controls from Bangladesh by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Sanger sequencing. Genotypes and allele frequencies were compared by performing chi-squared or Fisher's exact test with Yates' continuity correction. Serology for Campylobacter jejuni and anti-GM1 antibodies were determined by enzyme-linked immunosorbent assay (ELISA) techniques.

RESULTS

NOD variants (NOD1-Glu266Lys and NOD2- [Arg702Trp; Gly908Arg]) were not associated with susceptibility and severity of GBS when compared with healthy controls and mild or severe form of disease. Moreover, NOD2 polymorphisms showed wild-type NOD2 C2104 and NOD2 G2722, respectively, with homozygous Arg/Arg genotype of NOD2 (Arg702Trp) polymorphism and homozygous Gly/Gly genotype of NOD2 (Gly908Arg) for all study subjects in Bangladesh. Homogenous distribution of NOD1 genotypes was observed in patients with axonal and demyelinating form of GBS.

CONCLUSIONS

NOD variants confer no risk to the susceptibility and severity of GBS. Moreover, NOD2 polymorphism is rare or absent in patients with GBS as well as in the healthy individuals of Bangladesh.

A genome-wide survey of NOD-like receptors in Chinese tongue sole (Cynoglossus semilaevis): Identification, characterization and expression analysis in response to bacterial infection

As intracellular pathogen recognition receptors (PRRs), nucleotide-binding domain, leucine-rich repeat containing receptors (NLRs, NOD-like receptors) are involved in innate immune responses in vertebrates. However, there is no systemic study on NLRs in Chinese tongue sole (Cynoglossus semilaevis), a popular maricultured fish in China. In the present study, a genome-wide survey of NLRs was performed in C. semilaevis, with the identification of 29 NLRs, including five genes from the NLR-A subfamily (referred to as CsNOD1-5), two genes from the NLR-B subfamily, 18 genes from the NLR-C subfamily (referred to as CsNLR-C1 to 18) and four other NLR genes. Phylogenetic analysis implied that CsNOD1-5 contained conserved functional domains and had orthologous relationships with human NOD1-5. Moreover, CsNLR-C genes all possessed the FISHNA domain, which is a fish-specific NACHT subdomain. Expression analysis showed that CsNOD1-5 and CsNLR-C1/2 were ubiquitously expressed in various normal tissues. Bacterial infection with Vibro harveyi revealed distinct expression patterns of all the tested CsNLRs in gill, intestine, trunk kidney, liver and spleen. In particular, CsNOD1-4 and CsNLR-C2 were significantly upregulated in gills at 48 h post bacterial infection. In addition, CsNOD3 and CsNOD4 were significantly elevated in infectious intestine, trunk kidney, liver and spleen, revealing that their expressions were more sensitive to bacterial infection than other CsNLRs. Together with the computational protein-protein interaction network of CsNLRs, it was suggested that individual NLR genes had different roles in the innate immune cascades of C. semilaevi against bacterial infection. This study provides valuable information for further studies on CsNLR immune function.

Association of NOD1 and NOD2 polymorphisms with Guillain-Barré syndrome in Northern Indian population

BACKGROUND

Nucleotide oligomerization domain (NOD) proteins are cytosolic pattern recognition receptors that respond to bacterial substrate and induce NF-κB activation in host. Association of NOD polymorphisms have been studied in many autoimmune disorders, however its role in Guillain-Barré syndrome (GBS) remains unknown. We have investigated NOD1 Glu266Lys and NOD2 (Arg702Trp and Gly908Arg) gene polymorphisms among patients with GBS.

MATERIALS AND METHOD

Polymorphisms in NOD-1 (Glu266Lys) and NOD-2 (Arg702Trp and Gly908Arg) genes were studied using polymerase chain reaction-restriction fragment length polymorphism in 105 patients with GBS and 100 healthy controls.

RESULTS

Homozygous genotype (Lys/Lys) of NOD1 was significantly associated with GBS (p=0.013); and its subtypes viz. acute motor axonal neuropathy (AMAN) and acute inflammatory demyelinating polyneuropathy (AIDP) (p=0.008 and p=0.024 respectively) than controls. In NOD2 (Arg702Trp and Gly908Arg) polymorphisms, only heterozygous genotype (Arg/Trp and Gly/Arg) showed significant association with GBS (p=0.001 and p=0.01 respectively); subtypes AMAN, acute motor-sensory axonal neuropathy (AMSAN) and AIDP showed association with heterozygote Arg702Trp (p=0.001; p=0.029 and p=0.001 respectively) whereas only AIDP was associated with heterozygote genotype Gly908Arg (p=0.003).

CONCLUSION

NOD1 (Glu266Lys) and NOD2 (Arg702Trp and Gly908Arg) polymorphisms were associated with an increased susceptibility to GBS. These polymorphisms could be genetic marker to GBS susceptibility.

Characterization of NLR-A subfamily members in miiuy croaker and comparative genomics revealed NLRX1 underwent duplication and lose in actinopterygii

The NOD-like receptors (NLRs, nucleotide-binding domain and leucine-rich repeat containing receptors) are a recently identified family of intracellular pathogen recognition receptors in vertebrates. Several subfamilies of NLRs have been characterized in mammals and implicated in immunity and apoptosis, but studies of NLRs in teleost species have been lacking. Here we analyzed three NLR-A subfamily members from miiuy croaker: NLRC3, NLRC5, and NLRX1. Structural analysis showed that miiuy croaker NLR-A subfamily members own the feature of 5'UTR intron which may influence their role in enhancing translation level. Comparative analysis revealed NLRX1 duplicated into NLRX1a and NLRX1b, then NLRX1a was lost in actinopterygii and NLRX1b formed NLRX1 that now we called. Simultaneously, molecular evolutionary analysis indicated that the ancestral lineages of NLRX1 in tetrapod and actinopterygii under positive selection pressure. The positively sites in actinopterygii are mainly located in NACHT domain which was the critical region for signal transduction, suggesting that the evolution of NLRX1 gene in the ancestor of actinopterygii is beneficial in immune response. Pathogens challenge demonstrated that the expressions of NLRC3 and NLRC5 in miiuy croaker were induced not only by Vibrio anguillarum but also by poly (I:C), whereas NLRX1 exhibited more sensitive response to bacteria than virus.